This invention relates to improved hinges in plastic containers made of polystyrene or the like, and particularly to improved hinges which are self-attaching to the container and which releasably detain the cover of a container in a closed position.
Molded polystyrene foam containers are widely used as containers. They are light weight and relatively inexpensive and can be molded to various desired shapes. For instance, products are often protected by molding a polystyrene container to their form.
Molded polystyrene containers have a substantial drawback in that the molded polystyrene is somewhat soft and incapable of supporting conventional hinges, latches or the like which require screws, rivets or other similar fasteners to secure them to the container. The molded polystyrene foam simply breaks away from such fasteners and will not hold them. Therefore, the tops and bottoms of molded polystyrene foam containers have usually been connected by tape or the like, which is not reusable and is otherwise unsatisfactory in many obvious respects.
Hinges and latches for polystyrene boxes are described in copending U.S. application Ser. No. 822,416 filed Aug. 8, 1977, now U.S. Pat. No. 4,089,467 granted May 16, 1978, assigned to the same assignee as this application. Those hinges provide a viable means of hingedly attaching a cover to a polystyrene container, although the hinges of the invention herein have improved self-attachment to the polystyrene container and its associated cover. The latches used to maintain the lid in its closed position are also viable and useful structures, but inherently require additional parts over the basic hinge.